Sulfide species treatment of thin film photovoltaic cell and manufacturing method

Abstract

A method for forming a thin film photovoltaic device. The method includes providing a transparent substrate comprising a surface region, forming a first electrode layer overlying the surface region, forming a copper layer overlying the first electrode layer and forming an indium layer overlying the copper layer to form a multi-layered structure. The multi-layered structure is subjected to a thermal treatment process in an environment containing a sulfur bearing species to forming a copper indium disulfide material. The copper indium disulfide material comprising a copper-to-indium atomic ratio ranging from about 1.2:1 to about 2:1 and a thickness of substantially copper sulfide material having a copper sulfide surface region. The thickness of the copper sulfide material is selectively removed to expose a surface region having a copper poor surface comprising a copper to indium atomic ratio of less than about 0.95:1. The method subjects the copper poor surface to a sulfide species to convert the copper poor surface from an n-type semiconductor characteristic to a p-type semiconductor characteristic. A window layer is formed overlying the copper indium disulfide material.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application No. 61 / 103,239, filed Oct. 6, 2008, entitled “SULFIDE SPECIES TREATMENT OF THIN FILM PHOTOVOLTAIC CELL AND MANUFACTURING METHOD” by inventor HOWARD W. H. LEE, commonly assigned and incorporated by reference herein for all purposes. This application is related to U.S. Provisional Patent Application No. 61 / 103,549, filed Oct. 7, 2008, commonly assigned and incorporated by reference herein for all purposes. This application is also related to U.S. application Ser. No. 12 / 567,704, filed Sep. 25, 2009, commonly assigned and incorporated by reference herein for all purposes.STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicableREFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK[0003]Not applicableBACKGROUND OF THE INVENTION[0004]The present invention relates ...

AI Technical Summary

Benefits of technology

[0014]Many benefits are achieved by ways of present invention. For example, the present invention uses starting materials that are commercially available to form a thin film of semiconductor bearing material overlying a suitable substrate member. The thin film of semiconductor bearing material can be further processed to form a semiconductor thin film material of desired characteristics, such as atomic stoichiometry, impurity concentration, carrier concentration, doping, and others. In a specific embodiment, the band gap of the resulting copper indium disulfide material is about 1.55 eV. Additionally, the present method uses environmentally friendly materials that are rela

Problems solved by technology

Unfortunately, the supply of petrochemical fuel is limited and essentially fixed based upon the amount available on the planet Earth.

Additionally, as more people use petroleum products in growing amounts, it is rapidly becoming a scarce resource, which will eventually become depleted over time.

Although solar energy is environmentally clean and has been successful to a point, many limitations remain to be resolved before it becomes widely used throughout the world.

However, crystalline materials are often costly and difficult to make on a large scale.

Additionally, devices made from such crystalline materials often have low energy conversion efficiencies.

Similar limitations exist with the use of thin film technology in making solar cells.

That is, efficiencies are often poor.

Additionally, film reliability is often poor and cannot be used for extensive periods of time in conventional environmental applications.

Often, thin films are difficult to mechanically integrate with each other.

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